JP4094424B2 - Optical input device that measures finger movement - Google Patents

Abstract

An optical input device for measuring the movement of a finger (15) ia accommodated in a housing provided with a transparent window (12) for transmitting a measurement beam (13) from a diode laser (3) to the finger and radiation reflected by the finger to a detector (4). This feature prevents that grease and dust disturb and block the measuring beam.

Description

によって与えられる。
この式において、
Ｋは、外部の空洞共振器への結合係数であり、それは、レーザー空洞共振器から連結される放射の量を示し、
νは、レーザー放射の周波数であり、
ｖは、測定ビームの方向における指の速度であり、
ｔは、時間の瞬間であり、及び
ｃは、光速度である。
【００６６】
式を、上述の二つの論文に開示されている自己混合効果の理論から導出することができる。図６における矢印１６によって示すように、対象の表面は、それ自体の平面で移動する。ドップラー偏移がビームの方向における対象の移動に対してのみ起こるので、この移動１６は、それがこの方向における成分１６’を有するようなものであるはずである。それによって、ＸＺ平面、即ち図６の図面の平面における移動を測定することは可能になり、その移動は、Ｘ移動と呼ばれ得る。図６は、対象の表面がシステムの残りに関して斜めの位置を有することを示す。実際には、通常、測定ビームは、斜めのビームであり、対象の表面の移動は、ＸＹ−平面で起こることになる。Ｙ−方向は、図６における図面の平面に垂直である。この方向における移動を、第二のダイオードレーザーによって放出される第二の測定ビーム、及び第二のダイオードレーザーに関連する第二のフォトダイオードによって捕捉される散乱された光によって測定することができる。図５ａに示すように、（一又は複数の）斜めの照明ビームは、レンズ１０に関して偏心して（一又は複数の）ダイオードレーザーを配置することによって得られる。
【００６７】
モニターダイオードによって後部のレーザー面で放射の強度を測定することにより、指の移動によって引き起こされるレーザー空洞共振器の利得の変動を測定することは、最も単純で、よって最も魅力的な方法である。従来、このダイオードは、レーザー放射の強度を一定に保つために使用されるが、ここでは、それは、指の移動を測定するためにもまた、使用される。
【００６８】
利得の変動、よって指の移動を測定する別の方法は、レーザー放射の強度がレーザーの接合における電導帯中の電子の数に比例するという事実を利用する。次には、この数は、接合の抵抗に反比例する。この抵抗を測定することによって、指の移動を決定することができる。この測定方法の実施例を、図８において説明する。この図では、ダイオードレーザーの活性層を引用符３５によって表示し、このレーザーを供給するための電流源を、引用符３６によって表示する。ダイオードレーザーを横切る電圧は、コンデンサー３８を介して電子回路４０に供給される。レーザーを通じた電流で規格化されたこの電圧は、レーザー空洞共振器の抵抗、即ちインピーダンスに比例する。ダイオードレーザーと直列のインダクタンス３７は、ダイオードレーザーを横切る信号に対して高いインピーダンスを形成する。
【００６９】
移動の量、即ち指が移動すると共に時間に関して測定された速度を積分することで測定することができる距離、に加えて、移動の方向もまた検出しなければならない。これは、指が移動の軸に沿って前方へ移動するか後方へ移動するかを決定しなければならないことを意味する。移動の方向を、自己混合効果から結果として生じる信号の形状を決定することによって、検出することができる。図７におけるグラフ３２によって示すように、この信号は、非対称性の信号である。グラフ３２は、対象１５がレーザーに向って移動している状況を表す。上昇する傾き３２’は、下降する傾き３２’’よりも急勾配である。Ａｐｐｌｉｅｄ Ｏｐｔｉｃｓ，Ｖｏｌ．３１，Ｎｏ．８，２０ Ｊｕｎｅ １９９２，３４０１−３４０８頁における上述の論文に記載されるように、非対称性は、レーザーから離れる対象の移動に対しては逆になり、即ち下降する傾きが、上昇する傾きよりも急勾配である。自己混合信号の非対称性のタイプを決定することによって、指の移動の方向を確かめることができる。ある一定の状況の下で、例えば指のより小さな反射係数又は指とダイオードレーザーとの間のより大きな距離に対して、自己混合信号の形状又は非対称性を決定することは困難になる場合もある。
【００７０】
移動の方向を決定する別の好適な方法において、レーザー放射の波長λが、ダイオードレーザーの温度、よってそれを通じる電流に依存するという事実を使用する。例えば、ダイオードレーザーの温度が増加するとすれば、レーザー空洞共振器の長さは増加し、増幅される放射の波長は、増加する。図９の曲線４５は、放出される放射の波長λの温度（Ｔ_ｄ）依存性を示す。この図では、水平軸Ｔ_ｄ及び垂直軸λの両方が、任意の単位である。
【００７１】
図１０に示すように、グラフ５０によって表わされる周期的な駆動電流Ｉ_ｄがダイオードレーザーに供給されるとすれば、ダイオードレーザーの温度Ｔ_ｄは、グラフ５２に示すように、周期的に上昇し下降する。これは、対象によって反射されてある一定の時間遅れと共に空洞共振器に再び入る放射に関して、周期的に変動する周波数、よって連続的に変動する位相偏移を有するレーザー空洞共振器における定在光学波に帰着する。駆動電流の何れの半周期においても、ここでは、連続な時間セグメントがあり、ここで、ダイオードレーザーの利得は、空洞共振器における波の位相関係及び空洞共振器に再び入る反射された放射に依存して、より高くより低い。これは、図１０のグラフ５４に示すような放出された放射の時間依存の強度の変動（Ｉ）に帰着する。このグラフは、静止した即ち移動しない対象に対する状況を表す。第一の半周期１／２ｐ（ａ）におけるパルスの数は、第二の半周期１／２ｐ（ｂ）におけるパルスの数に等しい。
【００７２】
指の移動は、レーザー空洞共振器に再び入る放射のドップラー偏移を引き起こす、即ち、この周波数は、移動の方向に依存して増加するか、又は減少する。一つの方向、前方方向における指の移動は、再び入る放射の波長の減少を引き起こし、反対方向における移動は、この放射の波長における増加を引き起こす。レーザー空洞共振器における光学波の周期的な周波数の変調の効果は、ドップラー偏移がレーザー空洞共振器における周波数の変調と同じ符号を有する場合において、空洞共振器に再び入るドップラー偏移した放射の効果が、前記周波数の変調及びドップラー偏移が反対の符号を有する場合においてこの放射が有する効果とは異なることである。二つの周波数の偏移が同じ符号を有するとすれば、波と再び入る放射との間における位相差は、遅い速度で変化し、レーザー放射の結果として生じる変調の周波数は、より低い。二つの周波数の偏移が反対の符号を有するとすれば、波と放射との間の位相差は、より速い速さで変化し、レーザー放射の結果として生じる変調の周波数は、より高い。駆動レーザー電流の第一の半周期１／２ｐ（ａ）の間に、発生するレーザー放射の波長は、増加する。後方へ移動する指の場合には、再び入る放射の波長もまた増加するので、空洞共振器における波の周波数と、この空洞共振器に再び入る放射のものとの間の差は、より低い。よって、再び入る放射の波長が、発生する放射の波長に適合する時間セグメントの数は、放出されたレーザー放射の電気的な変調の欠如の場合におけるよりも小さい。これは、指が後方の方向に移動するとすれば、第一の半周期におけるパルスの数は、変調を適用しないとするよりも小さいことを意味する。第二の半周期１／２ｐ（ｂ）において、ここでは、レーザー温度及び発生する放射の波長が減少するが、再び入る放射の波長が、発生する放射のものに適合する時間セグメントの数は、増加する。よって、後方へ移動する指に対して、第一の半周期におけるパルスの数は、第二の半周期におけるパルスの数よりも小さい。これを、図１１のグラフ５８において説明するが、そのグラフは、対象が後方の方向に移動するとすれば放出されるレーザー放射の強度Ｉ_ｂを示す。このグラフを図１０のグラフ５４と比較することは、第一の半周期におけるパルスの数が減少したと共に、第二の半周期におけるパルスの数が増加したことを示す。
【００７３】
指が、指によって散乱されると共にレーザー空洞共振器に再び入る放射の波長がドップラー効果によって減少する、前方の方向に移動するとすれば、第一の半周期１／２ｐ（ａ）におけるパルスの数は、第二の半周期１／２ｐ（ｂ）におけるパルスの数より大きいことは、上記の推論から明らかであると思われる。
これを、前方へ移動する指の場合に放出される放射の強度Ｉ_ｆを表す図１１のグラフ５６を比較することにより確認することができる。電子処理回路において、第二の半周期１／２ｐ（ｂ）の間に数えられたフォトダイオード信号のパルスの数を、第一の半周期１／２ｐ（ａ）の間に数えられたパルスの数から減じる。結果として生じる信号が零であるとすれば、指は静止している。結果として生じる信号が正であるとすれば、指は、前方の方向に移動し、この信号が負であるとすれば、指は、後方の方向に移動する。結果として生じるパルスの数は、それぞれ前方及び後方の方向における移動の速度に比例する。
【００７４】
ある一定の状況の下で、例えば、レーザーと指との間の光路長が比較的小さく、電気的な変調の周波数及び振幅が比較的小さいのに対して、検出される移動が、比較的速いとすれば、ドップラー効果によって発生するパルスの数が、電気的な変調によって発生するパルスの数より高いことが起こる場合もある。このような状況で、第一の半周期の間におけるパルスの数を第二の半周期の間におけるパルスの数と比較することによって、移動の方向をまだ検出することができる。しかしながら、そのとき、速度は、これらの二つの数の差に比例しない。このような状況における速度を決定するために、前記二つの数を平均するべきであり、一定の値を、結果から減じるべきである。このようにして得られる数は、速度に対する尺度である。当業者は、この計算を実行するための電子回路を容易に設計することができる。
【００７５】
図９及び１０を参照して記載される実施例に使用される三角形の形状の駆動電流Ｉ_ｄの代わりに、長方形の形状のような、別の形状の駆動電流もまた使用してもよい。
【００７６】
また、利得の変動が、ダイオードレーザー空洞共振器の抵抗の変動を測定することによって決定されるとすれば、上述の指の移動の速度及び方向を測定する方法を使用することができる。
【００７７】
測定方法は、小さなドップラー偏移、例えば、波長の点では、１，５．１０^−１６ｍ程度の偏移、のみを要求し、それは６８０ｎｍのレーザー波長に対して１００ｋＨｚ程度のドップラー周波数の偏移に相当する。
【００７８】
一つの平面における二つの垂直な（Ｘ及びＹ）方向、即ち測定軸に沿った対象の移動を、図５ａ及び５ｂの入力デバイスで測定することができ、そのデバイスは、垂直な配向における二つのダイオードレーザー及び関連するフォトダイオードを含む。デバイスに第三のダイオードレーザー及び関連するフォトダイオードを加えることは、このデバイスが、第三のＺ−方向即ち測定軸に沿った移動を測定することもまた可能とする。第三の照射ビームがウィンドウ１２及び指に垂直に入射すると共に、他の方向における成分を有さないように、第三のダイオードレーザーをレンズ１０の光軸上に配置してもよい。そして、Ｚ方向に対する最適な測定信号を得てもよい。Ｘ及びＹ測定信号の信頼度及び確度を増加させるために、三つのダイオードレーザーは、好ましくは、一つの円上に１２０°の相互の角距離で配置される。この配置は、図１２に示され、ここで、第三のダイオードレーザー及び第三のフォトダイオードは、それぞれ引用符７及び８によって表示される。フォトダイオード４、６及び８の出力信号即ち抵抗測定信号を、それぞれＳ_４、Ｓ_６、及びＳ_８によって表すとすれば、Ｘ、Ｙ、及びＺ測定軸に沿った指の速度Ｖ_ｘ、Ｖ_ｙ、及びＶ_ｚを、それぞれ、例えば、次の
【００７９】
【数２】

ように計算することができる。
【００８０】
この計算を行うための電気回路は、加算する及び減算する素子を含むと共に、実施することが比較的容易である。
【００８１】
このようにして得られる速度の値、及び移動の時間の持続に関する積分によるＸ及びＹ方向における移動の距離は、それらが少なくとも二つのフォトダイオードの出力信号を平均することの結果であるので、より信頼できると共により正確である。わずかに指を持ち上げることのような、移動の誤差即ち望まれない移動は、フォトダイオードの出力信号に同様の効果を有する。Ｘ及びＹ測定軸に沿った移動を互いから出力信号を減じることによって決定すると、Ｘ及びＹ測定信号における望まれない移動の影響は、除去される。三つのフォトダイオードの出力信号を加えることによって得られるＺ−測定信号Ｖ_ｚのみは、指の上／下移動を示す。
【００８２】
Ｚ方向における人間の指及び入力デバイスの互いに対する移動が、クリック機能を行うために使用されるアプリケーションにおいて、それは、このような移動が起こることを検出するには十分である。指の変位の正確な測定は、Ｚ−測定がやや粗くてもよいように、必ずしも必要ではない。 移動の方向さえ検出する必要がない。
【００８３】
どんな必要条件も、入力デバイスに対して移動する指の構造又は反射係数に対して、ほとんど設定する必要がない。一枚の白紙及びデバイスの相対的な移動もまた容易に測定することができることは、論証されてきた。
【００８４】
光学的な観点から、光モジュールの寸法は、非常に小さくてもよい。入力デバイスの大きさは、主として、デバイスにおいて、容易な多量製造の態様によって組み込まれなければならないエレクトロニクスの量によって決定される。実際的な実施例では、ウィンドウは、３ｍｍ乃至５ｍｍ平方の大きさを有する。このデバイスにおいて使用される測定原理のために、その構成要素を、正確に整列する必要がなく、そのことは大量生産に対する大きな利点である。
【００８５】
図５ａ及び５ｂの実施例において、レンズ１０を、ポリカーボネート（ＰＣ）又はポリメタクリル酸メチル（ＰＭＭＡ）のように、ガラス又は透明なプラスチック材料で作ってもよい。このようなレンズを、透明な接着剤層１１、例えばエポキシによって、ダイオードレーザー、フォトダイオード、及び処理回路部品を所持する基板に固定することができる。この実施例に対して、ダイオードレーザーは、これらのレーザーがＶＣＳＥＬタイプであってもよいように、垂直方向に放射することを仮定する。このようなレーザーを、ワイヤーボンディング技術によって台板に容易に置くことができる。
【００８６】
好ましくは、水平な空洞共振器を有する、より従来の側面放出ダイオードレーザーを、それらが比較的かなり安価であるので、使用する。このようなレーザーを、それが垂直方向に放射するようにして、実装することができる。例えば、レーザーを、小さなテーブルに実装することができる。しかしながら、側面放射ダイオードレーザーを、それらが水平方向に放出するようにして、実装することもまた可能である。図１３ａは、このようなレーザーをもつ入力デバイスの実施例の垂直な断面であり、図１３ｂは、このデバイスのより低い部分の上面図である。これらの図では、１は、台又はハウジング板であり、それから電気接触ピン６２が突き出る。この台板は、それがダイオードレーザー用の冷却素子として機能することができるように、熱電導を有する。図５ａ及び５ｂ並びに１２に概略的に示す、電子回路部品を、シリコン又は別の材料の層６０に実装してもよく、その層は、回路基板を形成する。また、図５ａ及び５ｂの実施例は、このような層を含んでもよい。素子３、５、及び７は、側面放出ダイオードレーザーである。これらのレーザーの各々に対して、レンズ１０を通じてデバイスの頂部におけるウィンドウ１２へ向って垂直方向にダイオードレーザーからの水平に放出されたビーム６８、７０を反射する、反射部材６４が提供される。好ましくは、反射素子は、それらがまたいくらかの光学パワーを有すると共に入射の発散するビーム６８、７０をあまり発散しないか若しくは平行な又はさらにわずかに収束するビームに変換するように、球面形状を有する。そのとき、レンズ１０の光学パワーは、図５ａ及び５ｂの実施例におけるレンズ１０のものよりも小さくできる。また、図１３ａ及び１３ｂの実施例において、レンズ１０は、ガラスレンズであってもよいが、好ましくはプラスチックレンズである。プラスチックレンズはガラスレンズよりも安価であると共に軽く、厳格な光学的な必要条件をこのレンズに設定しないので、このアプリケーションにおいては非常に適切である。プラスチックで作られてもよく、凸の透明なウィンドウ１２が提供されるキャップ６６は、ハウジング板１と一緒に、デバイスのハウジングを形成する。測定ビームを集束させるために必要とされるレンズのパワーの一部分は、キャップ６６に含まれる場合もある。三つの、又は二つのダイオードレーザーのみを使用する場合には、二つの反射部材を、反射コーティングによってカバーされる一つのプラスチックリングによって構成してもよい。前記リングは、台板１の統合された部分を形成してもよい。そして、入力デバイスは、主としてプラスチック材料からなり、容易に組み立てることができる三つの構造部分のみで構成される。これらの部分は、反射リングが提供される台板１、接触ピン６２及びダイオードレーザー及び関連するフォトダイオード、並びに、レンズ１０及びウィンドウ１２が提供されるキャップ６６である。
【００８７】
図１４は、入力デバイスの好適な実施例を示し、ここでさらなる部分の統合が実行されてきた。この実施例では、図１３ａの実施例のキャップ６６及びレンズ１０は、単一のプラスチック素子７０に取り替えられ、その下側は、台板へ向って湾曲する。この曲面は、図１３ａにおけるレンズ１０と同じ、照射ビームにおける屈折効果を有する。図１４の実施例のより低い部分の上面図は、この部分が図１３ａ及び１３ｂのものと同じであるので、示してない。図１４に示す実施例は、たった二つの構造部分で構成されると共に、実施例が図１３ａ及び１３ｂに示すよりも組み立てることはさらにより容易である。
【００８８】
実施例が図１２、１３ａ、１３ｂ、１４、１５ａ及び１５ｂに示すことにおいて、測定ビームは、ウィンドウの平面に集束されない。測定ビームは、この平面におけるキズ及び残留する塵及びグリースが測定ビームを実質的に乱すことを予防するために、この平面において十分大きい断面を有する。これらのビームが、台板レベルにおける異なる位置から生ずると、照射ビームは、作用平面、例えばウィンドウの平面における異なる位置に照射スポットを形成する。照射ビーム及びそれらの散乱された放射は、十分に空間的に分離されるので、異なる測定軸間のクロストークは、本入力デバイスにおいては問題はない。必要であれば、残留するクロストークを、わずかに異なる波長をもつダイオードレーザーを使用することによって減少させることができる。この目的のために、数ｎｍの波長差は、既に十分である。
【００８９】
クロストークを除去する別の可能性は、一つのレーザーのみが任意の瞬間に作動することを引き起こす、ダイオードレーザー用の制御系の使用に対してある。多重化駆動回路は、その回路は異なるダイオードレーザーを交互に作動させるが、このような制御系を構成してもよい。このような多重化回路は、ダイオードレーザーの各々の範囲内に配置されると共に時分割モードで使用される一つの検出器又はフォトダイオードによって、二つ又は三つのダイオードレーザーのをモニターすることを可能にする。このような駆動回路をもつ実施例の追加の利点は、回路部品に必要とされる間隔及びデバイスの電力消費を減少させることである。
【００９０】
図１５ａ及び１５ｂは、入力デバイスの実施例を示し、ここで照射ビームは、光ファイバーによってウィンドウまでガイドされる。図１５ａは、垂直な断面であり、図１５ｂは、この実施例の上面図である。ファイバー７２、７３、及び７４の入力端は、周知の方法で、それぞれダイオードレーザー３、５、及び７に光学的に連結する。ファイバーの全ての出力端は、デバイスのウィンドウに位置する。ファイバーを、固体材料、例えばエポキシ、又は別の透明若しくは不透明な材料のキャップ７８に埋め込んでもよい。これらのファイバーの各々は、関連するダイオードレーザーからの照射の放射及びこのレーザーに戻る散乱された放射の両方に対して、このファイバーによってガイドされた放射に対するアイソレーターを形成する。結果として、異なる測定軸間のクロストークの可能性は、零に対して非常に小さい。ファイバーの他の利点は、それらが柔軟であることであり、そのことは、設計の可能性を増加させ、またそれらが、任意の距離にわたって放射を輸送することができるので、ダイオードレーザー及びフォトダイオードを入力デバイスのウィンドウからかなり遠隔な距離に配置することができることである。図１５ａ及び１５ｂの実施例では、ダイオードレーザー及び関連するフォトダイオードが、共に接近して配置される。これらの素子を、図１５ａに示すように、個別の区画７９に配置してもよく、その区画は、キャップと同じ材料又は別の材料であってもよい。
【００９１】
ファイバーの代わりに、他のライトガイド、例えば透明又は不透明な材料の本体におけるチャンネルを使用してもよい。
【００９２】
図１２−１５ｂの実施例には、三つの代わりに、二つのダイオードレーザーを提供してもよい。これは、入力デバイスがＸ及びＹ移動のみを測定しなければならず例えばクリック機能に関するＺ測定は必要とされない場合であると思われる。ダイオードレーザーの代わりに、他の小さなレーザーデバイスを使用してもよく、他の小さな放射に敏感なデバイスが、フォトダイオードに取って替わってもよい。
【００９３】
上述の入力デバイスを低コストで製造することができると、大量消費装置で実施されることは非常に適切である。その非常に小さな大きさ及び軽量のために、このデバイスを、既存の装置に容易に統合することができ、それによってこれらの装置の性能を、それらのコスト及び重量を実質的に増加させることなく、それらのもともとの設計を変化させることなく、増加させる。
【００９４】
図１６は、新しい入力デバイスの第一の重要なアプリケーション、即ち携帯又はセル方式の電話装置８０を示す。この装置の前側の面は、ダイヤルエントリー及び他の機能に関する多くのボタンスイッチ８３を含む、キーエントリーセクション８２が提供される。ディスプレイデバイス８５は、セクション８２上に配置され、アンテナ８７は、電話８０の最上面に提供される。テンキーダイヤルのようなダイヤル又は別のコマンドが、ボタンスイッチ８３から入力されるとき、入力されるコマンドに関する情報は、電話内の示してない送信回路及びアンテナを介して電話会社の基点へ送信される。蓄積されたリストの与えられた電話番号を選択すること、又は標準メッセージの表のから与えられたメッセージを送ることのように、電話回路部品に設けられた異なる機能を作動させるために、ボタンスイッチを介して入力される他のコマンドを電話の回路部品内で処理してもよい。ディスプレイデバイス８５を横切るカーソル８８の移動を制御するために電話装置に入力デバイス及び追加の回路部品を提供することによって、既存の機能のいくつかを、より容易な方法で行うことができ、新しい機能を作成することができる。入力デバイス８９を、そのウィンドウのみを図１６に示すが、電話におけるいくつかの位置に、例えば図１６に示すようにボタンスイッチより下に、又は側面の一つに配置してもよい。好ましくは、入力デバイスのウィンドウは、電話装置を保持するために指が通常置かれる位置の一つに位置する。装置の回路部品は、機能のメニューを表示することができ、デバイス８９の入力ウィンドウを横切る指の移動は、カーソル８８を、与えられた機能に移動させることができる。ウィンドウに垂直な方向における指を単一の移動、例えばクリックは、この機能を作動させることができる。
【００９５】
ＷＡＦプロトコル又はＩ−モードインターネットプロトコルのような標準プロトコルが提供される携帯電話に統合されるとき、入力デバイスは、大きな利点を提供することができる。このようなプロトコルによって、装置を、インターネットのような世界的なコミュニケーションネットワーク用に端末として使用することができる。これがますます広く広げられ使用されるようになると、新しいエンドユーザーの装置に関する要望がある。第一の候補は、セットトップボックス及び携帯電話が装備されたテレビ受像機である。新しい目的のために、これらの装置には、例えばテレビのリモートコントロールユニット又は携帯電話において良好に合う小さな入力デバイスが装備されるべきである。本入力デバイスは、完全にこれらの必要条件を満たす。
【００９６】
また、この入力デバイスを、携帯電話装置におけるのと同じ目的に関して、コードレス電話装置において使用することができる。コードレス電話装置９０を、図１７に示す。この装置は、電話又はケーブルネットワークに接続される基点９２、及び、基点から例えば１００ｍ未満の半径のエリア内に使用することができる移動可能な装置９４で構成される。装置９４は、キーエントリーセクション９５及びディスプレイデバイス９７を含む。携帯電話装置に記載されるのと同様な方法で、装置９４には、上述のような入力デバイス９９を提供することができる。図１７においてもまた、入力デバイスのウィンドウのみを示す。携帯電話装置のように、装置９４は、小さいと共に軽量であるべきである。コードレス電話装置における本入力デバイスの実施は、特にコードレスの装置に例えばインターネットへのアクセス用のＷＡＰプロトコル又はＩ−モードプロトコルが提供されるとすれば、携帯電話装置におけるその実施と同じ利点を提供する。図１８に示す、受信機及びディスプレイ装置１０１並びにリモートコントロールユニット１０７を含む従来のテレビ受像機１００を、セットトップボックス１０５をそれに加えることによって、インターネットコミュニケーションに関して適切にすることができる。このボックスは、電話又はケーブルネットワークを介してインターネットへのアクセスを提供すると共に、インターネットから受信した信号を、インターネット情報を表示するためにテレビ受像機によって処理することができる信号に変換する。テレビインターネットのユーザーが、手近にインターネットコマンド用の入力デバイスを有するべきであるので、この入力デバイスを、リモートコントロールに統合するべきである。本発明によれば、前述のような光入力デバイス１０９は、リモートコントロールユニット１０７に設けられる。ウィンドウのみが示されるデバイス１０９を、リモートコントロールユニットの従来のボタンの間に、又はリモートコントロールユニットを保持する人間の任意の指の範囲内における任意の他の位置に配置してもよい。
【００９７】
また、本発明の入力デバイスを、従来の手動のトラックボールマウス又はマウスパッドに取って替わるために、コンピューターの構成において使用してもよい。図１９は、ＬＣＤディスプレイ１１６と共に基礎部分１１２及びカバー部分１１５を含む、ノート又はラップトップとして知られるポータブルコンピューターを示す。基礎部分は、異なるコンピューターモジュール及びキーボード１１３を収容する。このキーボードにおいては、本発明の光入力デバイス１１９が配置され、従来のマウスパッドに取って替わる。入力デバイスは、従来のマウスパッドの位置に、又は任意の他の容易にアクセス可能な位置に、配置してもよい。入力デバイスが、二つの方向のみにおける指の移動を測定するために使用され、よって従来のマウスパッドの機能のみを行わなければならないとすれば、それは、二つのダイオードレーザーのみを含む必要がある。好ましくは、三つのダイオードレーザーを含む入力デバイスが使用され、よって、それがまたノートの従来のクリックボタンに取って代わるようにクリック機能を有する。
【００９８】
ハンドヘルド即ちパームトップコンピューターは、ノートのより小さなバージョンである。また、このようなパームトップコンピューターには、例えばディスプレイのスクリーンに触れるためのペンに取って替わるために、本発明による光入力デバイスを提供してもよく、そのペンは、表示されたメニューの機能を選択するために通常適用される。光入力デバイスは、パームトップコンピューターのキーボードに、しかしカバーの内側にもまた、配置してもよい。
【００９９】
図２０は、デスクトップコンピューターの構成１２０を示し、ここで光入力デバイスを、従来のトラックボールマウスに取って替わるために、いくつかの方法で適用することができる。コンピューターの構成は、キーボード１２１、コンピューターボックス１２２、及びモニター１２３で構成される。モニターは、図に示すような、支持物１２４に固定されたフラットＬＣＤモニター又はＣＲＴモニターであってもよい。好ましくは、光入力デバイス１２９は、キーボードに統合されるので、個別のマウス１２６及びコンピューターボックスへのそのケーブルは、もはや必要とされない。
【０１００】
上述のコンピューターの構成において、入力デバイスは、キーボード部分における代わりに、ディスプレイ部分に、例えば図１９のラップトップコンピューターのカバー１１５に、又はパームトップコンピューターのカバーに、配置してもよい。また、入力デバイスは、コンピューターディスプレイ以外のディスプレイに組み込んでもよい。
【０１０１】
既に述べたように、例えば図１６の携帯電話の入力デバイスを、メニューチャートをスクロールするための上下のスクロールスイッチにおいて使用することができる。また、このような入力デバイスは、上下スイッチによって制御されるカーソルによって指定されるメニューを作動させる、クリックを決定する性能を有してもよい。このような入力デバイスには、速く新しい開発を可能にする分離した構成要素を容易に設けることができる。
【０１０２】
図２１は、スクロール及びクリックの入力デバイス１３０の第一の実施例を示す。それは、二つのレーザー／ダイオードユニット１３１、１３２を含み、それらの各々は、ダイオードレーザー及びフォトダイオードを含む。このようなユニットの代わりに、また個別のダイオードレーザー及びフォトダイオードを使用してもよい。ユニット１３１及び１３２によって放出された放射の経路の各々に、ウィンドウ１４２の凸面ＣＷＳであってもよい作用平面１３７において関連するユニット１３１及び１３２の放射ビーム１３５及び１３６を集束させる、レンズ１３３及び１３４がそれぞれ配置される。このウィンドウは、デバイスが使用される、装置のハウジング１３９の一部分、例えば図２２における側面図に示すような携帯電話、を形成してもよい。レーザー／ダイオードユニット及び関連するレンズを、ビーム１３５及び１３６の主光線が、ウィンドウ１４２の法線に関して対頂角、例えばそれぞれ＋４５°及び−４５°の角度にあるように、配置してもよい。
【０１０３】
人間の指１３８は、スクローリング及び／又はクリッキング作用に対する作用平面を横切って移動する。上述のように、両方の作用は、レーザー／ダイオードユニット１３１及び１３２へ向って指によって反射された放射にドップラー偏移を引き起こす。これらのユニットの検出器の出力信号は、信号処理及びレーザー駆動電子回路部品１４０に供給される。この回路部品は、制御する指１３８の移動を評価し、その出力１４１におけるこれらの移動に関する情報を供給する。レーザー／ダイオードユニット１３１及び１３２、レンズ１３５及び１３６、ウィンドウ１４２、及び電子回路部品１４０及びソフトウェアを、一つのモジュールで統合してもよい。このモジュールは、スクローリング及びクリッキング機能が提供されるべきである携帯電話又は別の装置において、このように置かれる。分離した素子をもつ入力デバイスを実施することもまた可能である。特に、信号処理の一部分は、携帯電話又はリモートコントロール、コードレス電話、若しくはポータブルコンピューターのような他の装置の一部分を形成するマイクロコントローラー又は他の制御手段によって実行してもよい。
【０１０４】
前述のように、レーザー／ダイオードユニットから離れて向かう指又は他の対象の移動を、レーザー電流を変調することによって、及び検出器によって受信されるパルスを数えることによって、検出してもよい。それぞれビーム１３５及び１３６の主光線に沿った指の速度を表わす、これらの検出器の出力信号Ｓｉｇｎ_１及びＳｉｇｎ_２から、ウィンドウに平行な速度（Ｖ_{ｓｃｒｏｌｌ}）及びウィンドウに垂直な速度（Ｖ_{ｃｌｉｃｋ}）を、次の
【０１０５】
【数３】

のように計算することができる。
【０１０６】
図２３は、スクロール及びクリック入力デバイス１５０の第二の実施例を示す。この実施例は、二つのレンズ１３３及び１３４並びにウィンドウ１４２を単一の構成要素１５２に取り替えてきたという点で図２１及び２２のものと異なる。この素子は、ウィンドウを形成する、その凸の上面に両方のビーム１３５及び１３６を集束させる。
【０１０７】
図２１−２３の入力デバイスがスクローリング機能のみをモニターすることを必要とするとすれば、原則として、一つのダイオードレーザー、レンズ、及び検出器のみが要求される。
【図面の簡単な説明】
【図１】 フラットウィンドウを有する光入力デバイスの一部分を示す。
【図２】 このようなデバイスに対する本発明によるウィンドウの第一の実施例を示す。
【図３】 本発明によるウィンドウの第二の実施例を示す。
【図４】 本発明が実施される第一の既知の入力デバイスを示す。
【図５ａ】 本発明が実施される第二の最近提案された入力デバイスの第一の実施例を断面で示す。
【図５ｂ】 このデバイスの上面図である。
【図６】 入力デバイスの測定方法の原理を説明する。
【図７】 デバイス及び指の互いに対する移動の関数として光の周波数及びレーザー空洞共振器の利得の変動を示す。
【図８】 この変動を測定する方法を説明する。
【図９】 光のフィードバックをもつレーザーの温度の関数としてレーザー波長の変動を示す。
【図１０】 レーザーに対する周期的に変動する駆動電流の使用の効果を示す。
【図１１】 移動の方向を検出する方法を説明する。
【図１２】 三つの測定軸をもつ入力デバイスの図を示す；
【図１３ａ】 第二の入力デバイスの第二の実施例を示す。
【図１３ｂ】 第二の入力デバイスの第二の実施例を示す。
【図１４】 このデバイスの第三の実施例を示す。
【図１５ａ】 このデバイスの第四の実施例を示す図である。
【図１５ｂ】 このデバイスの第四の実施例を示す。
【図１６】 入力デバイスが装備された携帯電話を示す。
【図１７】 入力デバイスが装備されたコードレス電話を示す。
【図１８】 入力デバイスが装備されたテレビ受像機を示す。
【図１９】 入力デバイスが装備されたラップトップコンピューターを示す。
【図２０】 入力デバイスが装備されたデスクトップコンピューターを示す。
【図２１】 スクローリング及びクリッキング用の入力デバイスの第一の実施例を示す。
【図２２】 スクローリング及びクリッキング用の入力デバイスの第一の実施例を示す。
【図２３】 このようなデバイスの第二の実施例を示す。[0001]
The present invention relates to an optical input device for measuring finger movement along at least one measurement axis, which device is provided with a transparent window and contains at least one laser for generating a measurement beam. An optical means for focusing the measurement beam on the working plane, and a conversion means for converting the measurement beam radiation reflected by the finger into an electrical signal representative of movement along the measurement axis.
[0002]
The invention also relates to an apparatus comprising such an optical input device.
[0003]
The working plane is understood to mean the plane in which the measuring beam is in contact with the finger and is affected by the movement of the finger. In most situations, the working plane will be a plane through the top of the window, but it may also be a plane near this window.
[0004]
An optical input device as defined is known, for example, from European patent application EP-A0942285. This document describes a light mouse that is used in a computer configuration to move a cursor across a computer display or monitor, for example, to select a function of a displayed menu. In general, such a light mouse is moved across the mouse pad by hand, like a conventional mechanical mouse. In EP-A0942285 it is also proposed to use the optical device as a “reversed” optical mouse. The optical device is then stationary, for example on a desktop or notebook or palm computer keyboard, with a human finger moving across a transparent window in the optical device housing. In the latter case, the input device may be small because the optical module for measuring finger movement can be made very small. In practice, the input device is reduced to a light measurement module. This opens the way to new applications for input devices. For example, an input function may be provided on a mobile phone to select functions on a menu and to access an Internet page in a remote control device for a television receiver for the same purpose or in a virtual pen. it can. The light measuring device of EP-A092285 includes a flat window. Such flat windows can cause problems in the actual use of finger controlled input devices.
[0005]
The object of the present invention is to solve these problems and to provide a user-friendly finger-controlled optical input device that is also very suitable for use in non-ideal situations.
[0006]
The optical input device is characterized in that the upper surface of the window is convex in at least one of two mutually perpendicular directions in the working plane at the top of the window.
[0007]
The present invention recognizes that placing a finger on a flat window will be a problem because the user would have kept his eyes on the display so he cannot see the surface in which the window is embedded. Based. Furthermore, in bad light situations, the window will be hardly identifiable by the eye. Another recognition is that dust and dirt particles may collect on the window, especially in the central part where one or more measurement beams should pass. Dust and dirt will affect one or more measurement beams, thus affecting the measurement results and in the worst case making the measurement impossible. According to the invention, if the window has a convex surface shape, it can keep it clean in at least one direction, in particular in its central part through which one or more measuring beams pass. Furthermore, since the window here is tangible, it can be found by the finger itself and thus also in the darkness.
[0008]
A first embodiment of the optical input device is characterized in that the window is convex in both two directions.
[0009]
Not only is the two-dimensional convex surface resembling a regular lens surface, but the surface of the window can also be given a lens function.
[0010]
A preferred optical input device embodiment in terms of window performance is characterized in that the window is convex in one direction and concave in the other direction.
[0011]
Here, it may be arranged that the direction in which the surface of the window is convex, or the direction in which this surface is concave, the convex and concave directions are parallel to the axis of measurement. Thus, the user knows that in that direction the finger should be moved to activate a given function, such as menu or file scrolling.
[0012]
The optical input device may be further characterized in that the refractive index of the upper surface of the window is close to that of water.
[0013]
This feature makes it possible to reduce the effects of scratches on the window surface, which can be caused by wear and continuous use in non-ideal situations. The human finger oozes a substance consisting mainly of water, and if the finger is placed on the surface of the window, this water fills the scratches present on the surface.
The closer the refractive index of the surface material is to the refractive index of water, the smaller the effect of the scratch on the measurement beam.
[0014]
Another possibility to reduce the effects of scratches and residual dust and dirt particles on one or more measurement beams is the implementation of the input device characterized in that the measurement beams are focused in a plane away from the top surface of the window Realized by example. When the measurement beam is focused below or above the surface of the window, the cross section of the beam at this surface location is much larger than the size of the dust or dirt particles, so this particle has a slight effect on the beam. You can only have
[0015]
The present invention can be used with any finger-controlled optical input device having a transparent window, such as the “reversed” optical mouse disclosed in EP-A0942285. In this device, homodyne or heterodyne detection is used. A diffraction grating is used that is placed close to the module window. The grating reflects a portion of the measurement beam radiation, preferably diffracted in one of the first order, to a detector that also receives a portion of the radiation reflected and scattered by the finger. The laser radiation diffracted in the first order by the grating is denoted as a local oscillator beam, and the detector uses this local oscillator beam to detect radiation from the finger coherently. The interference of the radiation reflected by the local oscillator beam and the finger reaching the detector gives rise to a beat signal from the detector, which is determined by the relative movement of the finger in the plane itself. The light measurement module of EP-A092285 includes a collimator lens, a focusing lens, and a pinhole aperture in addition to the grating in front of the detector, and these elements should be very accurately aligned . This complicates manufacturing and increases the cost of modules that are intended to be mass-consumed products.
[0016]
The preferred embodiment of the optical input device described above is based on another measurement principle, includes fewer components, is smaller and easier to manufacture. This optical input device has a laser cavity resonance in which the conversion means represents the relative movement of the finger and the input device along with the reflected measurement beam radiation reentering the laser cavity and the interference of optical waves in this cavity It is characterized by comprising a combination of measuring means for measuring changes during the operation of the resonator and a laser cavity resonator.
[0017]
This optical input device uses the so-called self-mixing effect in a diode laser. This is the phenomenon that the radiation emitted by the diode laser and re-entering the cavity of the diode laser induces variations in the laser gain and hence in the radiation emitted by the laser.
The finger and the input device move relative to each other such that the direction of movement has a component in the direction of the laser beam. In the movement of the finger and input device, the radiation scattered by the object gets a frequency different from the frequency of the radiation illuminating the object due to the Doppler effect. A portion of the scattered light is focused on the diode laser by the same lens that focuses the illumination beam on the finger. As some of the scattered radiation enters the laser cavity through the laser mirror, light interference occurs within the laser. This causes a fundamental change in the characteristics of the laser and emitted radiation. Parameters that vary due to the self-coupling effect are the power, frequency, and line width of the laser radiation, and the threshold gain of the laser. The result of the interference in the laser cavity is the fluctuation of the values of these parameters with a frequency equal to the difference between the two radiation frequencies. This difference is proportional to the finger speed. Thus, finger speed and finger displacement by integrating over time can be determined by measuring one value of the parameter. This method can be performed with only a few and simple components and does not require precise alignment of these components.
[0018]
The use of self-mixing effects to measure the velocity of objects, generally solids and fluids, is known per se. By way of example, Applied Optics, Vol. 27, no. 2, 15 January 1988, pages 379-385, “Small laser Doppler velocimetry based on the self-mixing effect in a diode laser”, and Applied Optics, Vol. 31, no. 8, 20 June 1992, page 3401. Refer to the article “Laser Doppler velocimeter based on the self-mixing effect in a coupled semiconductor laser theory”. To date, however, the use of self-mixing effects in finger-controlled input devices as defined above has not been proposed. This new application is based on the recognition that a measurement module that uses the self-coupling effect can be made very small and inexpensive, so that it can be easily attached to existing devices and equipment without much additional cost.
[0019]
An embodiment of an optical input device that makes it possible to measure movement and determine the direction of movement is an electronic means for determining the shape of the signal that represents the variation during operation of the diode laser cavity. It is characterized by including.
[0020]
This signal is an asymmetric signal, and the asymmetry for the forward movement is different from the asymmetry for the backward movement.
[0021]
For applications where it is difficult to determine the asymmetry of the self-mixing signal, another embodiment of the optical input device is used. This embodiment includes laser drive means for supplying a periodically varying current to the diode laser, and electronic means for comparing the first and second measurement signals with each other. And the second measurement signal is generated during the alternating first half-cycle and second half-cycle, respectively.
[0022]
The wavelength of the radiation emitted by the diode laser increases with increasing temperature and thus with increasing current through the diode laser, thus decreasing the frequency of this radiation. Periodically fluctuating current through the diode laser in combination with radiation from the object re-entering the laser cavity results in many radiation pulses per half cycle and thus many corresponding pulses in the measured signal. To do. If there is no relative movement of the input device and the object, the number of signal pulses is the same in each half cycle. If the device and object move relative to each other, the number of pulses in one half cycle is greater or less than the number of pulses in the next half period, depending on the direction of movement. By comparing the signal measured during one half period with the signal measured during the next half period, not only the speed of movement but also the direction of movement can be determined.
[0023]
The optical input device may include different measurement means for determining changes during operation of the laser cavity.
[0024]
A first embodiment of the optical input device is characterized in that the measuring means is a means for measuring fluctuations in the impedance of the laser cavity.
[0025]
A preferred embodiment of the optical input device is characterized in that the measuring means is a radiation detector for measuring the radiation emitted by the laser.
[0026]
The radiation detector may be arranged in such a way that it receives a part of the radiation of the measurement beam.
[0027]
However, this embodiment of the optical input device is preferably characterized in that the radiation detector is arranged on the side of the laser cavity opposite to the side on which the measurement beam is emitted.
[0028]
In general, diode lasers are provided with a monitor diode on their rear side. Typically, such monitor diodes are used to stabilize the intensity of the laser beam emitted on the front side of the diode laser. According to the invention, the monitor diode is used to detect changes in the laser cavity caused by the radiation of the measurement beam reentering the laser cavity.
[0029]
The number of measurement axes and the orientation of these axes is determined by the function performed by the optical input device.
[0030]
An embodiment of an optical input device for measuring finger movement along a measurement axis in the working plane or along a measuring axis perpendicular to the working plane, which comprises one diode laser and one detector It is characterized by that.
[0031]
An embodiment of an optical input device for determining finger movement along the measurement axis in the working plane and finger movement along the measuring axis substantially perpendicular to the working plane is a method comprising at least two diode lasers. And at least one detector.
[0032]
An embodiment of the optical input device for determining the movement of the finger along the first and second measurement axes in the working plane is characterized in that it comprises two diode lasers and at least one detector .
[0033]
An embodiment of an optical input device for determining the movement of a finger along a first and second measurement axis in the working plane and a third measuring axis substantially perpendicular to the working plane is a three diode It includes a laser and at least one detector.
[0034]
The embodiment of the optical input device makes it possible to determine both the scrolling action and the clicking action. The scrolling action is understood to mean the movement of the cursor up and down or down across the menu table. Such an effect can be realized by moving the finger in a given direction across the window of the input device. It is understood that the click action means that the menu specified by the cursor is activated. The click action can be realized by a single movement of the finger in a direction perpendicular to the action plane. This embodiment is at least one for determining the movement of a finger along two diode lasers and a first measuring axis in the working plane and a second measuring axis substantially perpendicular to the working plane. It includes two detectors.
[0035]
Instead, an embodiment for determining both scrolling and clicking effects is that it includes two diode lasers and at least one for determining finger movement along the first and second measurement axes. Including detectors, characterized in that their axes are at a vertical angle with respect to the normal of the working plane.
[0036]
An input device with one or two measurement axes may also be used to make other measurements than determining scrolling and / or clicking effects.
As will be described later, this device and other devices that utilize two or more measurement beams may be provided with separate detectors for each measurement beam. However, if time division is used, it is also possible to use the exact same detector for all measurement beams.
[0037]
With respect to structural aspects, the input device may have several examples. In a first embodiment, the optical means comprises a lens arranged on the one hand between the at least one laser and the associated detector, and on the other hand a working plane, the at least one laser positioned eccentrically with respect to the lens. It is characterized by being.
[0038]
The lens may be a rotationally symmetric lens or may have another shape. The position of the eccentricity of the laser or lasers relative to the lens element ensures that the measurement beam is incident on the device window at an acute angle so that the beam has a component along the associated measurement axis. For the following description, the term optical axis is introduced, which is understood to mean the axis of symmetry of the lens or module, which axis is perpendicular to the module window.
[0039]
An embodiment of an optical input device comprising such a lens and two diode lasers is further provided so that the lines from their center to the optical axis of the lens are at a substantially 90 ° angle with respect to each other. , May be arranged.
[0040]
Such an embodiment comprising three diode lasers is characterized in that the diode lasers are arranged such that the lines from their center to the optical axis of the lens are at an angle of substantially 120 ° with respect to each other. Also good.
[0041]
In an optical input device, a VCSEL (vertical cavity surface emitting laser) type diode laser may be used. Such a laser emits radiation in the vertical direction making it suitable for the device. However, currently such lasers are quite expensive, which is not very suitable for consuming mass products.
[0042]
For this reason, each diode laser is a laser that emits horizontally, and the device includes, for each diode laser, a reflective member that reflects the beam from the associated diode laser to the working plane. Priority is given to the featured input device.
[0043]
Horizontally emitting diode lasers are the most commonly used lasers and are much cheaper than VCSELs. Providing the device with a reflective member adds little to the cost of the device.
[0044]
An embodiment of an input device that can be manufactured relatively easily and at low cost is a base plate on which it is mounted at least one diode laser and an associated detector, a cap fixed to the base plate and including a window It is comprised with the lens accommodated in a member and a cap member, It is characterized by the above-mentioned.
[0045]
This embodiment consists of only three parts that can be easily assembled without strict alignment requirements.
An embodiment of the input device, which is easier to manufacture, is characterized in that the lens is integrated into a cap member having an inner surface curved towards the base plate.
[0046]
This embodiment consists of only two parts.
[0047]
These embodiments are preferably further characterized in that the base plate, the cap member and the lens are made of a plastic material.
[0048]
Components made of such materials may be cheap and light and are therefore suitable for consumer products. Only the lens or window material should be transparent and have some optical quality.
[0049]
An alternative embodiment, i.e. without a lens, is characterized in that each diode laser is connected to the entrance side of a separate light guide and its exit side is positioned in the window of the device.
[0050]
In this embodiment, the radiation of the illumination beam is well isolated from its environment so that crosstalk between movements along different axes is eliminated or strongly reduced.
[0051]
This embodiment is preferably characterized in that the light guide is an optical fiber.
The optical fiber is flexible, has a small cross section and exhibits little attenuation per unit of length, thus allowing positioning of the device window at a greater distance from the diode laser and detector.
[0052]
Different input devices, such as in a mouse for a desktop computer, in a keyboard for a desktop or laptop computer, in a remote control unit for different devices, as in a mobile phone, etc., as defined in claims 27-31 May be used in applications.
[0053]
These and other aspects of the invention will be apparent from and elucidated by way of non-limiting example with reference to the examples described hereinafter.
[0054]
FIG. 1 shows a vertical cross-section of a portion of a finger-suppressed optical input device ID that includes a window W having a flat top surface FUS. The window is fixed to a window holder WH that forms part of the housing of the device or module. It also shows the user's finger UF moving across the window in the direction of the arrow displayed by the DOM. The optical components of the device are not shown in FIG. 1, but are shown in FIG. 4 and the following figure, showing different embodiments of the internal design of the input device. If dirt and dust particles and grease collect in the flat window and in the central part C of the window through which the measurement beam from the device and the radiation reflected by the finger should pass, as indicated by the mass PM There is also. The measurements made by the device will be affected by the mass M because the particles and the mass of grease will absorb and scatter radiation in an uncontrollable manner. In the worst case, this mass will absorb all the radiation to be measured so that no measurement is possible.
[0055]
According to the invention, as shown in the figure, this problem is eliminated by replacing the flat upper surface with a convex upper surface CUF. Here, particles and grease that may settle on the surface of the window will be removed from the central part and, under favorable circumstances, from the entire surface by the action of the fingers. The window will remain clean and will therefore exhibit sufficient transmission and a sufficiently low degree of scattering. Thus new problems are solved in a very efficient way by simple means.
[0056]
The surface may be convex in a direction perpendicular to the plane of the drawing in FIG. A window having such a two-dimensional convex shape resembles a regular plano-convex lens, for example. As this lens is provided with a lens function, it makes it possible to reduce the number of components of the input device, but this may be taken into account when designing the input device. Alternatively, the window may perform another function. This will be described with reference to FIG. 3, in which a top view of the window is shown at the top, a cross section along line AA ′ at the bottom left, and a cross section along line BB ′ on the right. The window is concave (CWS ′) in the direction AA ′ and convex (CWS) in the direction BB ′. The direction of the window can be linked to the X- and Y-movement of the finger, and thus to the horizontal and vertical movement of the cursor across the display, for example. Thus, the window provides an indication of direction. If the window is still convex in one direction, grease and dirt particles will not be close to the central part.
[0057]
As shown in FIGS. 2 and 3, the measurement BM is preferably focused, i.e., has its smallest cross-section, in a plane above this surface, rather than in a plane through the top of the top surface of the window. In the plane of the window, the cross section of the measurement beam is large enough to prevent irregularities in the surface of the window, such as scratches, from substantially disturbing the beam.
[0058]
Also, the effects of such scratches can be reduced to an acceptable level by appropriate selection of window material. Human fingers secrete substances that consist primarily of water. If there are scratches on the top of the window, the water will fill the scratches. The more the refractive index of the window material is equal to that of water, the less likely the scratches will be “seen” by the beam, ie the beam will be less affected by the scratches. Since the refractive index of water is low, if this possibility is used to gradually remove scratches, the window material is preferably a glass with a refractive index as low as possible.
[0059]
The present invention may be used with any optical input device having a transparent window through which the measurement beam passes. An example of such a device, “An inverted computer mouse ICM, is a copy of FIG. 5a, mostly from EP-A092285, and is different from FIG. 4 in that the surface of the window is convex instead of flat. At least the diffraction grating and the detector include an optical “chip” OC, a diode laser, which is mounted on the housing HO and looks at the fingertip through the window W. Input and output leads from the chip OC are electronic circuit components Connected to the printed circuit board PCB on which the EC is mounted, and mounted on the board PCB is a switch SWI operated by a push button PB, as in a conventional computer mouse. Connected to computer via cable CA as usual This device uses the principle of homodyne or heterodyne detection, a diffraction grating located near the window W reflects a part of the measurement beam to the detector, which part is used as a local oscillator beam The interference of this beam and the radiation reflected by the finger reaching the detector results in a beat signal from the detector, which is determined by the movement of the finger. , EP-A0942285.
[0060]
The optical chip or module OC includes, in addition to at least one grating, a collimator lens, a focusing lens, and a pinhole stop placed in front of the detector, which elements should be very accurately aligned. is there. As recently proposed by the applicant, the number of components in the optical input device can be reduced and its manufacture is simplified by using the principle of diode laser self-mixing in this device.
[0061]
FIG. 5a is a diagrammatic cross-section of an input device that uses this principle. The device comprises on its lower side a base plate 1 which is a carrier for one or more diode lasers, a VCSEL type laser in this embodiment, and one or more detectors, for example photodiodes. In FIG. 5a, only one diode laser 3 and its associated photodiode 4 are visible, but as shown in the top view of the apparatus of FIG. 5b, usually at least a second diode laser 5 and associated detector 6 are Provided on the base plate. Diode lasers 3 and 5 emit lasers or measure beams 13 and 17, respectively. On its upper side, the device is provided with a transparent window 12 over which a human finger 15 can be moved. A lens 10, for example a plano-convex lens, is placed between the diode laser and the window. This lens focuses the laser beams 13 and 17 on or near the transparent window. If the finger 15 is in this position, it scatters the beam 13. A part of the radiation of the beam 13 is scattered in the direction of the illumination beam 13, which is converged by the lens 10 at the emission surface of the diode laser 3 and reenters the cavity cavity of this laser. As will be explained hereinafter, the radiation returning to the cavity resonator induces a change in this cavity resonator, which results in a change in the intensity of the laser radiation emitted by the diode laser, among others. This change can be detected by the photodiode 4 which converts the variation of the radiation into an electrical signal and the electronic circuit components 18 for processing this signal. Also, the illumination beam 17 is focused on the object and scattered by it, and a part of the scattered radiation reenters the cavity resonator of the diode laser 5. The circuit components 18 and 19 for the signal of the photodiode 6 shown in FIGS. 5a and 5b are for illustrative purposes only and may be more or less conventional. As illustrated in FIG. 5b, the circuit components are interconnected.
[0062]
FIG. 6 illustrates the principle of the input device and the self-mixing effect when using horizontally emitting diode lasers and monitor photodiodes placed on the rear face of the laser. In this figure, a diode laser, for example the diode laser 3, is schematically represented by its cavity resonator 20 and its front and rear surfaces, ie laser mirrors 21 and 22, respectively. The cavity resonator has a length L. A finger whose movement can be measured is indicated by a quotation mark 15. The distance between this finger and the front surface 21 is the length L ₀ To form an external cavity resonator. The laser beam emitted through the front is indicated by the quotes 25 and the radiation reflected by the finger in the direction of the front is indicated by the quotes 26. A part of the radiation generated in the laser cavity resonator passes through the rear face and is captured by the photodiode 4.
[0063]
If the object 15 moves in the direction of the illumination beam 13, the reflected radiation 26 undergoes a Doppler shift. This means that the frequency of this radiation changes, i.e. a frequency shift occurs. This frequency shift depends on the speed at which the finger moves and is on the order of several kHz to MHz. The radiation whose frequency is re-entering the laser cavity interferes with the optical wave, ie the radiation generated in this cavity, ie a self-mixing effect occurs in the cavity. Depending on the amount of phase shift between the optical wave and the radiation re-entering the cavity, this interference will either strengthen or weaken, i.e. the intensity of the laser radiation increases periodically. Or decrease. The frequency of modulation of the laser radiation thus generated is exactly equal to the difference between the frequency of the optical wave in the cavity and that of the Doppler-shifted radiation that reenters the cavity. The frequency difference is on the order of a few kHz to MHz and is therefore easy to detect. The combination of self-mixing effect and Doppler shift causes variations in the behavior of the laser cavity. In particular, its gain, i.e., light amplification, varies.
[0064]
This will be described with reference to FIG. In this figure, the curves 31 and 32 represent the distance L between the finger 15 and the front mirror 21, respectively. ₀ Represents the variation in the frequency ν of the emitted laser radiation and the variation in the gain g of the diode laser. both ν and g and L ₀ Is an arbitrary unit. Distance L ₀ 3 is the result of finger movement, the abscissa in FIG. 3 can be reset on the time axis, and the gain is plotted as a function of time. The gain variation Δg as a function of the finger velocity v is given by
[0065]
[Expression 1]

Given by.
In this formula:
K is the coupling coefficient to the external cavity, which indicates the amount of radiation coupled from the laser cavity,
ν is the frequency of the laser radiation,
v is the speed of the finger in the direction of the measurement beam;
t is the moment of time, and
c is the speed of light.
[0066]
The equation can be derived from the theory of self-mixing effects disclosed in the above two papers. As indicated by arrow 16 in FIG. 6, the surface of the object moves in its own plane. This movement 16 should be such that it has a component 16 'in this direction, since the Doppler shift only occurs for the movement of the object in the direction of the beam. Thereby it is possible to measure the movement in the XZ plane, i.e. the plane of the drawing of FIG. FIG. 6 shows that the surface of the object has an oblique position with respect to the rest of the system. In practice, the measurement beam is usually an oblique beam and the movement of the surface of interest will occur in the XY-plane. The Y-direction is perpendicular to the plane of the drawing in FIG. Movement in this direction can be measured by the second measurement beam emitted by the second diode laser and the scattered light captured by the second photodiode associated with the second diode laser. As shown in FIG. 5 a, the oblique illumination beam (s) is obtained by placing the diode laser (s) eccentric with respect to the lens 10.
[0067]
Measuring the laser cavity resonator gain variation caused by finger movement by measuring the intensity of the radiation at the rear laser plane with a monitor diode is the simplest and therefore the most attractive method. Traditionally, this diode is used to keep the intensity of the laser radiation constant, but here it is also used to measure finger movement.
[0068]
Another method of measuring gain variation and thus finger movement takes advantage of the fact that the intensity of the laser radiation is proportional to the number of electrons in the conduction band at the laser junction. This number is then inversely proportional to the resistance of the junction. By measuring this resistance, finger movement can be determined. An example of this measurement method will be described with reference to FIG. In this figure, the active layer of the diode laser is indicated by quotation marks 35 and the current source for supplying this laser is indicated by quotation marks 36. The voltage across the diode laser is supplied to the electronic circuit 40 via the capacitor 38. This voltage, normalized by the current through the laser, is proportional to the resistance or impedance of the laser cavity. An inductance 37 in series with the diode laser creates a high impedance to the signal across the diode laser.
[0069]
In addition to the amount of movement, i.e. the distance that can be measured by integrating the speed measured with respect to time as the finger moves, the direction of movement must also be detected. This means that it must be determined whether the finger moves forward or backward along the axis of movement. The direction of movement can be detected by determining the shape of the signal resulting from the self-mixing effect. As shown by the graph 32 in FIG. 7, this signal is an asymmetric signal. The graph 32 represents the situation where the object 15 is moving toward the laser. The rising slope 32 'is steeper than the falling slope 32''. Applied Optics, Vol. 31, no. 8,20 June 1992, as described in the above paper at pages 3401-3408, the asymmetry is opposite to the movement of the object away from the laser, ie the descending slope is more than the rising slope. It is steep. By determining the type of asymmetry of the self-mixing signal, the direction of finger movement can be ascertained. Under certain circumstances, it may be difficult to determine the shape or asymmetry of the self-mixing signal, for example, for the smaller reflection coefficient of the finger or the greater distance between the finger and the diode laser. .
[0070]
Another preferred method of determining the direction of movement uses the fact that the wavelength λ of the laser radiation depends on the temperature of the diode laser and thus the current through it. For example, if the temperature of the diode laser increases, the length of the laser cavity increases and the wavelength of the amplified radiation increases. Curve 45 in FIG. 9 shows the temperature (T _d ) Show dependency. In this figure, the horizontal axis T _d And the vertical axis λ are arbitrary units.
[0071]
As shown in FIG. 10, the periodic drive current I represented by the graph 50. _d Is supplied to the diode laser, the diode laser temperature T _d As shown in the graph 52, it rises and falls periodically. This is a standing optical wave in a laser cavity having a periodically varying frequency and thus a continuously varying phase shift with respect to radiation that is reflected back by the object and reenters the cavity with a certain time delay. To return to. There is a continuous time segment here in any half-cycle of the drive current, where the gain of the diode laser depends on the wave phase relationship in the cavity and the reflected radiation reentering the cavity And higher and lower. This results in a time-dependent intensity variation (I) of the emitted radiation as shown in graph 54 of FIG. This graph represents the situation for a stationary or non-moving object. The number of pulses in the first half cycle 1 / 2p (a) is equal to the number of pulses in the second half cycle 1 / 2p (b).
[0072]
The finger movement causes a Doppler shift of the radiation that reenters the laser cavity, i.e., this frequency increases or decreases depending on the direction of movement. Movement of the finger in one direction, the forward direction, causes a decrease in the wavelength of re-entering radiation, and movement in the opposite direction causes an increase in the wavelength of this radiation. The effect of the periodic frequency modulation of the optical wave in the laser cavity is that of Doppler-shifted radiation that reenters the cavity when the Doppler shift has the same sign as the frequency modulation in the laser cavity. The effect is different from the effect this radiation has if the frequency modulation and the Doppler shift have opposite signs. If the two frequency shifts have the same sign, the phase difference between the wave and the re-entering radiation changes at a slower rate, and the frequency of modulation resulting from the laser radiation is lower. If the two frequency shifts have opposite signs, the phase difference between the wave and the radiation changes at a faster rate, and the frequency of modulation resulting from the laser radiation is higher. During the first half period 1 / 2p (a) of the drive laser current, the wavelength of the laser radiation generated increases. In the case of a finger moving backward, the wavelength of the re-entering radiation also increases, so the difference between the frequency of the wave in the cavity and that of the radiation re-entering the cavity is lower. Thus, the number of time segments in which the wavelength of re-entering radiation matches the wavelength of the generated radiation is smaller than in the case of a lack of electrical modulation of the emitted laser radiation. This means that if the finger moves in the backward direction, the number of pulses in the first half-cycle is smaller than if no modulation is applied. In the second half-cycle 1 / 2p (b), where the laser temperature and the wavelength of the generated radiation are reduced, the number of time segments in which the wavelength of the re-entering radiation matches that of the generated radiation is To increase. Thus, for a finger moving backwards, the number of pulses in the first half cycle is smaller than the number of pulses in the second half cycle. This is illustrated in the graph 58 of FIG. 11, which shows the intensity I of the laser radiation emitted if the object moves backwards. _b Indicates. Comparing this graph with graph 54 of FIG. 10 shows that the number of pulses in the first half cycle decreased and the number of pulses in the second half cycle increased.
[0073]
If the finger moves in the forward direction, the wavelength of radiation scattered by the finger and re-entering the laser cavity is reduced by the Doppler effect, the number of pulses in the first half-cycle 1 / 2p (a) It is apparent from the above inference that is greater than the number of pulses in the second half period ½p (b).
This is the intensity I of the radiation emitted in the case of a finger moving forward. _f It can confirm by comparing the graph 56 of FIG. In the electronic processing circuit, the number of pulses of the photodiode signal counted during the second half cycle ½p (b) is equal to the number of pulses counted during the first half cycle ½p (a). Subtract from the number. If the resulting signal is zero, the finger is stationary. If the resulting signal is positive, the finger moves in the forward direction, and if this signal is negative, the finger moves in the backward direction. The resulting number of pulses is proportional to the speed of movement in the forward and backward directions, respectively.
[0074]
Under certain circumstances, for example, the optical path length between the laser and the finger is relatively small and the frequency and amplitude of electrical modulation is relatively small, whereas the detected movement is relatively fast If so, it may happen that the number of pulses generated by the Doppler effect is higher than the number of pulses generated by electrical modulation. In such a situation, the direction of movement can still be detected by comparing the number of pulses during the first half-cycle with the number of pulses during the second half-cycle. However, then the speed is not proportional to the difference between these two numbers. To determine the speed in such a situation, the two numbers should be averaged and a constant value should be subtracted from the result. The number thus obtained is a measure for speed. One skilled in the art can easily design an electronic circuit to perform this calculation.
[0075]
The triangular shaped drive current I used in the embodiment described with reference to FIGS. _d Alternatively, another shape of drive current, such as a rectangular shape, may also be used.
[0076]
Also, if the gain variation is determined by measuring the resistance variation of the diode laser cavity, the above-described method for measuring the speed and direction of finger movement can be used.
[0077]
The measurement method is a small Doppler shift, eg, 1.5.10 in terms of wavelength. ^-16 Only a shift of about m is required, which corresponds to a shift of the Doppler frequency of about 100 kHz for a laser wavelength of 680 nm.
[0078]
The movement of the object along two vertical (X and Y) directions in one plane, i.e. along the measurement axis, can be measured with the input device of FIGS. Includes a diode laser and associated photodiode. Adding a third diode laser and associated photodiode to the device also allows the device to measure movement along a third Z-direction or measurement axis. The third diode laser may be disposed on the optical axis of the lens 10 so that the third irradiation beam is perpendicularly incident on the window 12 and the finger and does not have components in other directions. Then, an optimal measurement signal for the Z direction may be obtained. In order to increase the reliability and accuracy of the X and Y measurement signals, the three diode lasers are preferably arranged on a circle with a mutual angular distance of 120 °. This arrangement is shown in FIG. 12, where the third diode laser and the third photodiode are indicated by the quotes 7 and 8, respectively. The output signals of the photodiodes 4, 6 and 8, i.e. the resistance measurement signals, are respectively S ₄ , S ₆ And S ₈ Is represented by the finger velocity V along the X, Y, and Z measurement axes. _x , V _y And V _z For example, the following
[0079]
[Expression 2]

Can be calculated as follows.
[0080]
The electrical circuit for performing this calculation includes elements to add and subtract and is relatively easy to implement.
[0081]
The speed values obtained in this way, and the distance of movement in the X and Y directions due to the integral over the duration of the movement, are the result of averaging the output signals of at least two photodiodes. Reliable and more accurate. Movement errors or unwanted movements, such as lifting a finger slightly, have a similar effect on the output signal of the photodiode. By determining the movement along the X and Y measurement axes by subtracting the output signal from each other, the effects of unwanted movement in the X and Y measurement signals are eliminated. Z-measurement signal V obtained by adding the output signals of three photodiodes _z Only indicates finger up / down movement.
[0082]
In applications where the movement of a human finger and input device relative to each other in the Z direction is used to perform a click function, it is sufficient to detect that such movement occurs. Accurate measurement of finger displacement is not always necessary so that the Z-measurement may be somewhat rough. Even the direction of movement need not be detected.
[0083]
There is little need to set any requirement for the finger structure or reflection coefficient that moves relative to the input device. It has been demonstrated that the relative movement of a sheet of paper and the device can also be easily measured.
[0084]
From an optical point of view, the dimensions of the optical module may be very small. The size of the input device is largely determined by the amount of electronics that must be incorporated in the device by means of easy mass production. In a practical embodiment, the window has a size of 3 mm to 5 mm square. Due to the measurement principle used in this device, its components do not have to be precisely aligned, which is a great advantage for mass production.
[0085]
In the embodiment of FIGS. 5a and 5b, the lens 10 may be made of glass or a transparent plastic material, such as polycarbonate (PC) or polymethyl methacrylate (PMMA). Such a lens can be fixed to a substrate carrying a diode laser, a photodiode and a processing circuit component by means of a transparent adhesive layer 11, for example epoxy. For this example, it is assumed that the diode lasers emit in the vertical direction so that these lasers may be of the VCSEL type. Such a laser can be easily placed on the base plate by wire bonding technology.
[0086]
Preferably, more conventional side-emitting diode lasers with horizontal cavity resonators are used because they are relatively fairly inexpensive. Such a laser can be implemented such that it emits vertically. For example, the laser can be mounted on a small table. However, it is also possible to implement side-emitting diode lasers such that they emit horizontally. FIG. 13a is a vertical section of an embodiment of an input device with such a laser, and FIG. 13b is a top view of the lower portion of the device. In these figures, 1 is a pedestal or housing plate from which the electrical contact pins 62 protrude. This base plate has thermal conductivity so that it can function as a cooling element for the diode laser. Electronic circuit components, schematically shown in FIGS. 5a and 5b and 12, may be mounted on a layer 60 of silicon or another material, which layer forms a circuit board. The embodiment of FIGS. 5a and 5b may also include such a layer. Elements 3, 5, and 7 are side-emitting diode lasers. For each of these lasers, a reflecting member 64 is provided that reflects the horizontally emitted beams 68, 70 from the diode laser vertically through the lens 10 toward the window 12 at the top of the device. Preferably, the reflective elements have a spherical shape so that they also have some optical power and convert the incident diverging beams 68, 70 into less diverging or parallel or even slightly converging beams. . At that time, the optical power of the lens 10 can be smaller than that of the lens 10 in the embodiment of FIGS. 5a and 5b. 13a and 13b, the lens 10 may be a glass lens, but is preferably a plastic lens. Plastic lenses are cheaper and lighter than glass lenses and do not set strict optical requirements on these lenses, so they are very suitable for this application. A cap 66, which may be made of plastic and provided with a convex transparent window 12, together with the housing plate 1 forms the housing of the device. A portion of the lens power required to focus the measurement beam may be included in the cap 66. If only three or two diode lasers are used, the two reflective members may be constituted by a single plastic ring covered by a reflective coating. The ring may form an integrated part of the base plate 1. The input device is mainly made of a plastic material and is composed of only three structural parts that can be easily assembled. These parts are the base plate 1 on which the reflective ring is provided, the contact pins 62 and the diode laser and the associated photodiode, and the cap 66 on which the lens 10 and the window 12 are provided.
[0087]
FIG. 14 shows a preferred embodiment of the input device, where further part integration has been performed. In this embodiment, the cap 66 and lens 10 of the embodiment of FIG. 13a are replaced with a single plastic element 70, the lower side of which is curved towards the base plate. This curved surface has the same refractive effect on the illumination beam as the lens 10 in FIG. 13a. The top view of the lower part of the embodiment of FIG. 14 is not shown because this part is the same as that of FIGS. 13a and 13b. The embodiment shown in FIG. 14 consists of only two structural parts and is even easier to assemble than the embodiment is shown in FIGS. 13a and 13b.
[0088]
In the example shown in FIGS. 12, 13a, 13b, 14, 15a and 15b, the measurement beam is not focused in the plane of the window. The measuring beam has a sufficiently large cross section in this plane to prevent scratches and residual dust and grease in this plane from substantially disturbing the measuring beam. When these beams originate from different positions at the base plate level, the irradiation beams form irradiation spots at different positions in the working plane, for example the plane of the window. Since the illumination beams and their scattered radiation are sufficiently spatially separated, crosstalk between different measurement axes is not a problem with the present input device. If necessary, residual crosstalk can be reduced by using diode lasers with slightly different wavelengths. For this purpose, a wavelength difference of a few nm is already sufficient.
[0089]
Another possibility to eliminate crosstalk is for the use of a control system for a diode laser that causes only one laser to operate at any moment. The multiplexed drive circuit operates different diode lasers alternately, but may constitute such a control system. Such a multiplexing circuit can monitor two or three diode lasers with one detector or photodiode placed in each range of diode lasers and used in a time division mode. To. An additional advantage of embodiments having such a drive circuit is that it reduces the spacing required for circuit components and the power consumption of the device.
[0090]
Figures 15a and 15b show an embodiment of an input device where the illumination beam is guided to the window by an optical fiber. FIG. 15a is a vertical cross section and FIG. 15b is a top view of this embodiment. The input ends of fibers 72, 73, and 74 are optically coupled to diode lasers 3, 5, and 7, respectively, in a well-known manner. All output ends of the fiber are located in the device window. The fiber may be embedded in a cap 78 of a solid material, such as epoxy, or another transparent or opaque material. Each of these fibers forms an isolator for the radiation guided by the fiber, both for radiation from the associated diode laser and for scattered radiation returning to the laser. As a result, the possibility of crosstalk between different measurement axes is very small with respect to zero. Another advantage of fibers is that they are flexible, which increases the possibilities of design, and because they can transport radiation over any distance, diode lasers and photodiodes Can be located far away from the input device window. In the embodiment of FIGS. 15a and 15b, the diode laser and associated photodiode are placed close together. These elements may be placed in a separate compartment 79, as shown in FIG. 15a, which may be the same material as the cap or another material.
[0091]
Instead of fibers, other light guides may be used, for example channels in the body of transparent or opaque material.
[0092]
In the embodiment of FIGS. 12-15b, two diode lasers may be provided instead of three. This seems to be the case when the input device has to measure only the X and Y movements, for example no Z measurement for the click function is required. Instead of a diode laser, other small laser devices may be used, and other small radiation sensitive devices may replace the photodiode.
[0093]
If the input device described above can be manufactured at low cost, it is very appropriate to be implemented in a mass consuming device. Because of its very small size and light weight, this device can be easily integrated into existing equipment, thereby reducing the performance of these equipment without substantially increasing their cost and weight. Increase them without changing their original design.
[0094]
FIG. 16 shows a first important application of a new input device, namely a portable or cellular telephone device 80. The front side of the device is provided with a key entry section 82 that includes a number of button switches 83 for dial entry and other functions. Display device 85 is disposed on section 82 and antenna 87 is provided on the top surface of telephone 80. When a dial, such as a numeric keypad, or another command is input from the button switch 83, information regarding the input command is transmitted to a telephone company base point via a transmission circuit and an antenna not shown in the telephone. . Button switches to activate different functions provided in the telephone circuit components, such as selecting a given phone number in the stored list or sending a given message from the standard message table Other commands entered via the may be processed within the telephone circuit components. By providing the telephone device with input devices and additional circuitry to control the movement of the cursor 88 across the display device 85, some of the existing functions can be performed in an easier way and new functions Can be created. Although the input device 89 is shown only in its window in FIG. 16, the input device 89 may be placed in several positions on the telephone, for example below the button switch as shown in FIG. Preferably, the window of the input device is located at one of the positions where a finger is normally placed to hold the telephone device. The circuit components of the device can display a menu of functions, and movement of the finger across the input window of the device 89 can cause the cursor 88 to move to the given function. A single movement of the finger in a direction perpendicular to the window, for example a click, can activate this function.
[0095]
Input devices can offer significant advantages when integrated into mobile phones where standard protocols such as WAF protocol or I-mode Internet protocol are provided. Such a protocol allows the device to be used as a terminal for a global communication network such as the Internet. As this becomes increasingly widespread and used, there is a desire for new end-user equipment. The first candidate is a television receiver equipped with a set top box and a mobile phone. For new purposes, these devices should be equipped with small input devices that fit well, for example in television remote control units or mobile phones. The input device fully meets these requirements.
[0096]
The input device can also be used in a cordless telephone device for the same purpose as in a mobile phone device. A cordless telephone device 90 is shown in FIG. This device consists of a base point 92 connected to a telephone or cable network, and a mobile device 94 that can be used within an area of a radius of, for example, less than 100 m from the base point. Device 94 includes a key entry section 95 and a display device 97. The device 94 can be provided with an input device 99 as described above in a manner similar to that described for a mobile phone device. Also in FIG. 17, only the window of the input device is shown. Like a mobile phone device, the device 94 should be small and lightweight. The implementation of the present input device in a cordless telephone device provides the same advantages as its implementation in a mobile phone device, especially if the cordless device is provided with a WAP protocol or I-mode protocol for access to the Internet, for example. . The conventional television receiver 100 including the receiver and display device 101 and the remote control unit 107 shown in FIG. 18 can be made suitable for Internet communication by adding a set top box 105 thereto. This box provides access to the Internet via telephone or cable network and converts signals received from the Internet into signals that can be processed by a television receiver to display Internet information. Since TV Internet users should have an input device for Internet commands at hand, this input device should be integrated into the remote control. According to the present invention, the optical input device 109 as described above is provided in the remote control unit 107. The device 109, in which only the window is shown, may be placed between conventional buttons on the remote control unit or at any other location within the range of any finger of the person holding the remote control unit.
[0097]
The input device of the present invention may also be used in a computer configuration to replace a conventional manual trackball mouse or mouse pad. FIG. 19 shows a portable computer known as a notebook or laptop that includes a base portion 112 and a cover portion 115 along with an LCD display 116. The base part houses different computer modules and a keyboard 113. In this keyboard, the optical input device 119 of the present invention is arranged, replacing the conventional mouse pad. The input device may be placed at the location of a conventional mouse pad or at any other easily accessible location. If the input device is used to measure finger movement in only two directions and thus only has to perform the function of a conventional mouse pad, it needs to contain only two diode lasers. Preferably, an input device comprising three diode lasers is used, thus having a click function so that it also replaces the conventional click button of the notebook.
[0098]
A handheld or palmtop computer is a smaller version of a notebook. Such a palmtop computer may also be provided with a light input device according to the present invention, for example to replace a pen for touching the screen of the display, the pen being a function of the displayed menu. Usually applied to select. The light input device may be placed on the keyboard of the palmtop computer, but also inside the cover.
[0099]
FIG. 20 shows a desktop computer configuration 120 where the light input device can be applied in several ways to replace a conventional trackball mouse. The computer is composed of a keyboard 121, a computer box 122, and a monitor 123. The monitor may be a flat LCD monitor or CRT monitor fixed to a support 124 as shown. Preferably, the optical input device 129 is integrated into the keyboard so that a separate mouse 126 and its cable to the computer box are no longer needed.
[0100]
In the computer configuration described above, the input device may be placed on the display portion, for example on the cover 115 of the laptop computer of FIG. 19, or on the cover of the palmtop computer, instead of in the keyboard portion. The input device may be incorporated in a display other than the computer display.
[0101]
As already mentioned, for example, the input device of the mobile phone of FIG. 16 can be used in the up and down scroll switch for scrolling the menu chart. Such an input device may also have the ability to determine a click that activates a menu specified by a cursor controlled by an up / down switch. Such input devices can easily be provided with separate components that allow for rapid new development.
[0102]
FIG. 21 shows a first embodiment of the scroll and click input device 130. It includes two laser / diode units 131, 132, each of which includes a diode laser and a photodiode. Instead of such a unit, separate diode lasers and photodiodes may also be used. Lenses 133 and 134 focus the radiation beams 135 and 136 of the associated units 131 and 132 in the working plane 137, which may be the convex surface CWS of the window 142, in each of the paths of radiation emitted by the units 131 and 132. Each is arranged. This window may form part of the housing 139 of the device in which the device is used, for example a mobile phone as shown in the side view in FIG. The laser / diode unit and associated lens may be positioned such that the chief rays of the beams 135 and 136 are at an apex angle with respect to the normal of the window 142, eg, + 45 ° and −45 °, respectively.
[0103]
The human finger 138 moves across the working plane for scrolling and / or clicking effects. As described above, both actions cause a Doppler shift in the radiation reflected by the finger towards the laser / diode units 131 and 132. The output signals of the detectors of these units are supplied to signal processing and laser drive electronics 140. This circuit component evaluates the movement of the controlling finger 138 and provides information about these movements at its output 141. The laser / diode units 131 and 132, the lenses 135 and 136, the window 142, the electronic circuit component 140 and the software may be integrated in one module. This module is thus placed in a mobile phone or another device where scrolling and clicking functions should be provided. It is also possible to implement an input device with separate elements. In particular, part of the signal processing may be performed by a microcontroller or other control means forming part of a mobile phone or other device such as a remote control, cordless phone, or portable computer.
[0104]
As previously described, movement of a finger or other object away from the laser / diode unit may be detected by modulating the laser current and counting the pulses received by the detector. The output signal Sign of these detectors represents the velocity of the finger along the principal rays of beams 135 and 136, respectively. ₁ And Sign ₂ To the velocity parallel to the window (V _scroll ) And speed perpendicular to the window (V _click Next
[0105]
[Equation 3]

It can be calculated as follows.
[0106]
FIG. 23 shows a second embodiment of the scroll and click input device 150. This embodiment differs from that of FIGS. 21 and 22 in that the two lenses 133 and 134 and the window 142 have been replaced with a single component 152. This element focuses both beams 135 and 136 onto their convex upper surface forming a window.
[0107]
If the input device of FIGS. 21-23 needs to monitor only the scrolling function, in principle only one diode laser, lens and detector are required.
[Brief description of the drawings]
FIG. 1 illustrates a portion of an optical input device having a flat window.
FIG. 2 shows a first embodiment of a window according to the invention for such a device.
FIG. 3 shows a second embodiment of a window according to the invention.
FIG. 4 shows a first known input device in which the present invention is implemented.
FIG. 5a shows in cross-section a first embodiment of a second recently proposed input device in which the present invention is implemented.
FIG. 5b is a top view of the device.
FIG. 6 illustrates the principle of the input device measurement method.
FIG. 7 shows the variation in optical frequency and laser cavity gain as a function of device and finger movement relative to each other.
FIG. 8 illustrates a method for measuring this variation.
FIG. 9 shows the variation in laser wavelength as a function of the temperature of a laser with optical feedback.
FIG. 10 shows the effect of using a periodically varying drive current for the laser.
FIG. 11 illustrates a method for detecting the direction of movement.
FIG. 12 shows a diagram of an input device with three measurement axes;
FIG. 13a shows a second embodiment of the second input device.
FIG. 13b shows a second embodiment of the second input device.
FIG. 14 shows a third embodiment of this device.
FIG. 15a shows a fourth embodiment of the device.
FIG. 15b shows a fourth embodiment of this device.
FIG. 16 shows a mobile phone equipped with an input device.
FIG. 17 shows a cordless telephone equipped with an input device.
FIG. 18 shows a television receiver equipped with an input device.
FIG. 19 shows a laptop computer equipped with an input device.
FIG. 20 shows a desktop computer equipped with an input device.
FIG. 21 shows a first embodiment of an input device for scrolling and clicking.
FIG. 22 shows a first embodiment of an input device for scrolling and clicking.
FIG. 23 shows a second embodiment of such a device.

Claims (30)

An optical input device for measuring finger movement along at least one measurement axis,
A module for providing at least one laser for generating a measurement beam provided with a transparent window, optical means for focusing the measurement beam on a working plane, and measuring beam radiation reflected by the finger along the measurement axis Conversion means for converting into an electrical signal representing the movement,
An upper surface of the window, Ri convex der in at least one direction perpendicular to the two mutually in the working plane at the top of the window,
The optical input device , wherein the measurement beam is focused on a plane away from the upper surface of the window . An optical input device for measuring finger movement along at least one measurement axis and the direction of this movement ,
A module for providing at least one laser for generating a measurement beam provided with a transparent window, optical means for focusing the measurement beam on a working plane, and measuring beam radiation reflected by the finger along the measurement axis Conversion means for converting into an electrical signal representing the movement,
The top surface of the window is convex in at least one of two mutually perpendicular directions in the working plane at the top of the window;
It comprises laser driving means for supplying a periodically varying current to the diode laser, and electronic means for comparing the first and second measurement signals with each other;
The optical input device , wherein the first and second measurement signals are generated during alternating first and second half-cycles, respectively. The window is an optical input device according to claim 1 or 2, wherein the both of the two directions is convex. The window is an optical input device according to claim 1 or 2, wherein the in one of said directions is concave convex, and in other of said directions. The window is the refractive index of the upper surface of, claims 1 to 4 optical input device according to any one of the preceding, wherein the close to that of water.   The converting means is a reflected measurement beam radiation that reenters the laser cavity and the interference of optical waves in the cavity and represents the relative movement of the finger and the input device. 6. The optical input device according to claim 1, wherein the optical input device is constituted by a combination of measuring means for measuring a change during operation and the laser cavity resonator.   7. It measures the movement and the direction of the movement, characterized in that it comprises electronic means for determining the shape of the signal representative of fluctuations during operation of the diode laser cavity. The optical input device according to claim 1. The measuring means according to claim 1 to 7 optical input device according to any one characterized in that it is a means for measuring the variation of the impedance of the laser cavity.   9. The optical input device according to claim 1, wherein the measuring means is a radiation detector that measures radiation emitted by the laser. The optical input device according to claim 9 , wherein the radiation detector is disposed on a side surface of the laser cavity opposite to a side surface on which the measurement beam is emitted. It determines the movement of a finger along an axis in the working plane or along an axis perpendicular to the working plane, characterized in that it comprises a diode laser and a detector. The optical input device according to any one of 10 . It determines the movement of the finger along an axis in the working plane and the movement of the finger perpendicular to the working plane, characterized in that it comprises at least two diode lasers and at least one detector. The optical input device according to any one of 10 . It is characterized in that it comprises at least two diode lasers and at least one detector, any one of claims 1 to 10 to determine the movement of the finger along the first and second measuring axis in the action plane 1 The optical input device described. Movement of the finger along the first and second measuring axes in the working plane and a third measuring axis perpendicular to the working plane, characterized in that it comprises three diode lasers and at least one detector optical input device as claimed in any one of claims 1 to 10 to determine. It includes two diode lasers and at least one detector for determining finger movement along a first measurement axis in the working plane and a second measuring axis substantially perpendicular to the working plane. 13. An optical input device according to any one of claims 1 to 10 and 12 , characterized in that it determines both a scrolling action and a clicking action. It includes two diode lasers and at least one detector that determines finger movement along the first and second measurement axes;
14. An optical input device according to any one of claims 1 to 11 and 13, which determines both scrolling and clicking effects, characterized in that the axis is at a vertical angle with respect to the normal of the action plane. The optical means comprises, on the one hand, a lens arranged between the at least one diode laser and the associated detector, and on the other hand a working plane,
It said at least one laser according to claim 1 to 16 any one optical input device as claimed characterized in that it is positioned eccentrically with respect to the lens. Including two diode lasers,
18. The optical input device of claim 17 , wherein the diode lasers are arranged such that lines from their center to the optical axis of the lens are at an angle of substantially 90 degrees with respect to each other. Including three diode lasers,
18. The optical input device of claim 17 , wherein the diode lasers are arranged such that lines from their center to the optical axis of the lens are at an angle of substantially 120 degrees with respect to each other. Each diode laser is a diode laser that emits horizontally,
The device, for each diode laser, the associated from a diode laser the beam of claims 1 to 15 and 17 to 19 any one of claims, characterized in that it comprises a reflecting member for reflecting to said window Optical input device. It comprises a base plate on which the at least one diode laser and an associated detector are mounted, a cap member fixed to the base plate and including the window, and a lens accommodated in the cap member. 21. An input device according to any one of claims 1 to 15 and 17 to 20 . The input device according to claim 21 , wherein the lens is integrated with the cap member having an inner surface that curves toward the base plate. The input device according to claim 21 or 22 , wherein the base plate, the cap member, and the lens are made of a plastic material. Each diode laser is connected to the entrance side of a separate light guide,
The light guide outlet side claims 1 to 16 input device according to any one, characterized in that it is positioned in the window of the device. The input device according to claim 24 , wherein the light guide is an optical fiber. A mouse for a desktop computer comprising the input device according to any one of claims 1 to 25 . 26. A keyboard for a desktop computer with which the input device according to any one of claims 1 to 25 is integrated. 26. A laptop computer with which the input device of any one of claims 1 to 25 is integrated. 26. A display with which the input device according to any one of claims 1 to 25 is integrated. 26. A remote control unit in which at least one input device according to any one of claims 1 to 25 is integrated.

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